1. Field of the Invention
The present invention relates to a medical suture having micro cogs on a surface thereof and a method of manufacturing the medical suture.
2. Description of the Related Art
From the second half of the 1960s, in order to finish suturing tissue without knotting the suture, a barbed suture having barbs which are formed by cutting an outer portion of the suture has been tried to be used for suturing tissue. In the barbed suture, one or more micro cogs are formed on a surface of the suture at a predetermined interval. If the suture is inserted in one direction and tension is applied to pull the suture in the opposite direction, the barbs formed on the surface of the suture are firmly engaged with the tissue. Therefore, unlike a general suture, the barbed suture is used without knotting.
In the 1990s, Ruff in North Carolina of US and Sulamanidze in Russia published a new form of a medical barbed suture which could be used for surgical suturing, facelift for removing wrinkles in a face, a neck, a chest, and the like or pulling face tissue, and plastic surgery for removing wrinkles. In addition to the barbed suture, various medical sutures for anchoring tissue have been used for two purposes, that is, knot-free suturing and facelift.
As a representative method of manufacturing a barbed suture for surgical tissue suturing and plastic surgery, cutting methods are disclosed in US Patent No. 2004/0060410 titled by “Barbed Suture” and US Patent No. 2003/0041426 titled by “Method of Forming Barbs on a Suture and Apparatus for Performing Same”. The cutting method is currently widely used, and most of suture products are manufactured according to the cutting method. However, the cutting method has the shortcomings as follows. Since the barbs are formed by cutting the surface of a spun thread of the suture, there is a limitation in size and thickness of the barb; since a distal end of the barb is too sharp, stimulus may be exerted on tissues or nerves in the vicinity thereof; since the spun thread of the suture is damaged due to the cutting, the strength thereof is greatly decreased in comparison with the suture having the same size; and since bio-absorption of relatively slender barbs formed by the cutting method is speedily made, a tissue anchoring ability is easily lost.
In order to compensate for the structural shortcomings in the barb formation, U.S. Pat. No. 7,582,105 discloses “Suture for Wound Closure, Tissue Approximation, Tissue Support, Suspension and/or Anchoration”. In the invention, barbs are not formed in the suture, but knotting of the suture is performed with a predetermined interval, and a cone is suspended at each knot. However, in the invention, since the knots are formed in the suture, excessive folding and curving occur in the suture, and thus, the strength is greatly decreased at the knots, so that the function as a suture may be lost. In addition, the cone suspended to each knot is larger and harder than the barb. When the suture is inserted into a subcutaneous tissue, a patient may feel great pains due to damage to tissues and nerves.
Besides, US Patent No. 2006/005144 titled by “Tissue Holding Devices and Methods for Making the Same” discloses a pressing and die cutting method and an injection molding method as cited techniques. However, implementation of the invention is not assured, and the invention is not yet commercialized.
As described above, although various methods have been used for manufacturing a medical suture having a tissue anchoring function, the techniques for compensating for the shortcomings of the current products and capable of being immediately commercialized and practically used has been required to be developed.